package mongodb

import (
	"context"
	"errors"
	"github.com/globalsign/mgo"
	"github.com/globalsign/mgo/bson"
	"sort"
	"strconv"

	"git.aiterp.net/rpdata/api/models"
	"git.aiterp.net/rpdata/api/repositories"
)

type characterRepository struct {
	characters *mgo.Collection
	cidCounter *counter
	restoreIDs bool
}

func newCharacterRepository(db *mgo.Database, restoreIDs bool) (repositories.CharacterRepository, error) {
	collection := db.C("common.characters")

	err := collection.EnsureIndexKey("name")
	if err != nil {
		return nil, err
	}

	err = collection.EnsureIndexKey("shortName")
	if err != nil {
		return nil, err
	}

	err = collection.EnsureIndexKey("author")
	if err != nil {
		return nil, err
	}

	err = collection.EnsureIndex(mgo.Index{
		Key:      []string{"nicks"},
		Unique:   true,
		DropDups: true,
	})
	if err != nil {
		return nil, err
	}

	err = collection.EnsureIndex(mgo.Index{
		Key: []string{"$text:description"},
	})
	if err != nil {
		return nil, err
	}

	return &characterRepository{
		restoreIDs: restoreIDs,
		characters: collection,
		cidCounter: newCounter(db, "auto_increment", "Character"),
	}, nil
}

func (r *characterRepository) Find(ctx context.Context, id string) (*models.Character, error) {
	character := new(models.Character)
	err := r.characters.FindId(id).One(character)
	if err != nil {
		return nil, err
	}

	return character, nil
}

func (r *characterRepository) FindNick(ctx context.Context, nick string) (*models.Character, error) {
	character := new(models.Character)
	err := r.characters.Find(bson.M{"nick": nick}).One(character)
	if err != nil {
		return nil, err
	}

	return character, nil
}

func (r *characterRepository) FindName(ctx context.Context, name string) (*models.Character, error) {
	query := bson.M{
		"$or": []bson.M{
			{"shortName": name},
			{"name": name},
		},
	}

	// Look for all characters matching query
	characters := make([]*models.Character, 0, 8)
	err := r.characters.Find(query).All(&characters)
	if err != nil {
		if err == mgo.ErrNotFound {
			return nil, repositories.ErrNotFound
		}

		return nil, err
	} else if len(characters) == 0 {
		return nil, repositories.ErrNotFound
	}

	// Prioritize exact match
	for _, character := range characters {
		if character.Name == name {
			return character, nil
		}
	}

	return characters[0], nil
}

func (r *characterRepository) List(ctx context.Context, filter models.CharacterFilter) ([]*models.Character, error) {
	query := bson.M{}
	if filter.Author != nil {
		query["author"] = *filter.Author
	}
	if len(filter.IDs) > 0 {
		query["_id"] = bson.M{"$in": filter.IDs}
	}
	if len(filter.Nicks) > 0 {
		query["nicks"] = bson.M{"$in": filter.Nicks}
	}
	if len(filter.Names) > 0 {
		query["$or"] = []bson.M{
			{"name": bson.M{"$in": filter.Names}},
			{"shortName": bson.M{"$in": filter.Names}},
		}
	}
	if filter.Search != nil {
		query["$text"] = bson.M{"$search": *filter.Search}
	}

	characters := make([]*models.Character, 0, 32)
	err := r.characters.Find(query).Limit(filter.Limit).All(&characters)
	if err != nil {
		if err == mgo.ErrNotFound {
			return characters, nil
		}

		return nil, err
	}

	sort.Slice(characters, func(i, j int) bool {
		ni, _ := strconv.Atoi(characters[i].ID[1:])
		nj, _ := strconv.Atoi(characters[j].ID[1:])

		return ni < nj
	})

	return characters, nil
}

func (r *characterRepository) Insert(ctx context.Context, character models.Character) (*models.Character, error) {
	if !r.restoreIDs {
		nextId, err := r.cidCounter.Increment(1)
		if err != nil {
			return nil, err
		}
		character.ID = "C" + strconv.Itoa(nextId)
	} else {
		n, err := strconv.Atoi(character.ID[1:])
		if err != nil {
			return nil, err
		}

		err = r.cidCounter.Bump(n)
		if err != nil {
			return nil, err
		}
	}

	err := r.characters.Insert(&character)
	if err != nil {
		return nil, err
	}

	return &character, nil
}

func (r *characterRepository) Update(ctx context.Context, character models.Character, update models.CharacterUpdate) (*models.Character, error) {
	updateBson := bson.M{}
	if update.Name != nil {
		updateBson["name"] = *update.Name
		character.Name = *update.Name
	}
	if update.ShortName != nil {
		updateBson["shortName"] = *update.ShortName
		character.ShortName = *update.ShortName
	}
	if update.Description != nil {
		updateBson["description"] = *update.Description
		character.Description = *update.Description
	}

	err := r.characters.UpdateId(character.ID, bson.M{"$set": updateBson})
	if err != nil {
		return nil, err
	}

	return &character, nil
}

func (r *characterRepository) AddNick(ctx context.Context, character models.Character, nick string) (*models.Character, error) {
	if character.HasNick(nick) {
		return nil, errors.New("nick already exist")
	}

	match := bson.M{
		"_id":   character.ID,
		"nicks": bson.M{"$ne": nick},
	}

	err := r.characters.Update(match, bson.M{"$push": bson.M{"nicks": nick}})
	if err == mgo.ErrNotFound {
		return nil, repositories.ErrNotFound
	} else if err != nil {
		return nil, err
	}

	newNicks := make([]string, len(character.Nicks), len(character.Nicks)+1)
	copy(newNicks, character.Nicks)
	character.Nicks = append(newNicks, nick)

	return &character, nil
}

func (r *characterRepository) RemoveNick(ctx context.Context, character models.Character, nick string) (*models.Character, error) {
	if !character.HasNick(nick) {
		return nil, errors.New("nick does not exist")
	}

	match := bson.M{
		"_id":   character.ID,
		"nicks": nick,
	}

	err := r.characters.Update(match, bson.M{"$pull": bson.M{"nicks": nick}})
	if err == mgo.ErrNotFound {
		return nil, repositories.ErrNotFound
	} else if mErr, ok := err.(*mgo.LastError); ok && mErr.Code == 11000 {
		return nil, errors.New("The nick belongs to another character already")
	} else if err != nil {
		return nil, err
	}

	newNicks := make([]string, len(character.Nicks), len(character.Nicks)+1)
	copy(newNicks, character.Nicks)
	for i := range newNicks {
		if newNicks[i] == nick {
			newNicks = append(newNicks[:i], newNicks[i+1:]...)
			break
		}
	}
	character.Nicks = newNicks

	return &character, nil
}

func (r *characterRepository) Delete(ctx context.Context, character models.Character) error {
	return r.characters.RemoveId(character.ID)
}